Sectional piston



June 2, 1959 J. w. MARSHALL SECTIONAL'PISTON Filed Feb. 6. 1957 ELStE WISE MARSH/1 L1.

ADMIN/51m Taf/x fw tes SECTIONAL PISTON John W. Marshall, deceased, late of Bristol, Pa., by Elsie Wise Marshall, administratrix, Bristol, Pa.

The present invention relates to pistons of the type commonly included in an internal combustion engine and is concerned primarily with a sectional piston of novel construction and including a lubricating system.

It is well recognized that a piston is an essential element of the modern internal combustion engine. Such a piston is ordinarily mounted for reciprocation in a cylindrical chamber formed in the engine block and is connected through the medium of a connecting rod with the crank shaft of an engine. Moreover it is now common practice to employ piston rings to effect a good seal between the piston and the cylinder wall.

At the present time considerable difficulty is experienced in replacing worn piston rings due to the fact that such a change requires a complete removal of the piston from its cylindrical chamber.

With the foregoing conditions in mind, the present invention has in view as its foremost objective the provision of a piston of the type above noted which is of a sectional construction and which consists essentially of a head section and a skirt section with the two being detachably connected. The head section carries the piston rings. The skirt section embodies the connection to the connecting rod. Thus, it is obvious that the head section may be removed independently of the skirt section to permit of a change in the piston rings.

It is, of course, necessary that lubrication be provided for the relative sliding movement between the piston and the wall of the cylinder in which it reciprocates. Another object of the invention is to provide, in a sectional piston of the character aforesaid, a new and improved lubricating system which consists essentially of a supply duct that extends upwardly through the connecting rod and which communicates with a transverse passage in the wrist pin. A passage is provided from this latter passage to the outer wall of the piston.

Still another object of the invention is to provide in a sectional piston of the character aforesaid a skirt section that is formed on its outer surface with oil'retaining ducts which preferably take the form of annular grooves together with by-passes for connecting adjacent grooves.

During the normal operation of an internal combustion engine air is combined with gasoline to provide the fuel mixture in the form of a Vapor. This` air often has some moisture content. Thus, after a cylinder has been fired, there is a residue of condensed moisture in the form of water and any gasoline which has not been consumed by the combustion. This residue passes to the bottom of the cylinder and will be mixed with the lubricating oil. A further object of the invention Ais to provide a sectional piston of the character aforesaid with means for conducting the residue and oil to a separator or filter so as to purify the oil and render it t for reuse.

Various other more detailed objects and advantages of the invention such as arise in connection with carrying out the above noted ideas in a practical embodiment will in part become app-arent and in part be hereinafter stated as the description of the invention proceeds.

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The invention, therefore, comprises a sectional piston consisting essentially of a head section that is detachably mounted on a skirt section with the head section being provided with grooves for receiving piston rings and the skirt section carrying a Wrist pin to which a connecting rod is connected. The wrist pin and connecting rod are formed with communicating passages providing a 1ubricati-ng system while the outer surface of the skirt section is formed with oil ducts and provision is made for conducting a mixture of the residue of combustion and oil to a separator.`

For a full and more complete understanding of the invention reference may be had to the following description `and accompanying drawing wherein: l v

Figure 1 is a longitudinal section through a sectional piston as designed in accordance with the precepts of this invention; and

Figure 2 is a fragmentary sectional view of a modilication.

Referring now to the drawing wherein like reference characters denote corresponding parts and first more particularly to Figure 1, a portion of an engine block is represented at 10 and provides a cylindrical chamberV 11 which will be hereinafter identified as the cylinder. Mounted for reciprocation in this cylinder 11 is a sectional piston of this invention which comprises two main sections. These are the head section which is referred to in its entirety by the reference character H, and a skirt section which is identified in its entirety by the reference character S.

The head section H is of an inverted cup-shaped or hollow formation and comprises an end wall or head 12 to which is integrally joined a cylindrical wall 13. At its center, the head 12 is deformed to provide an inwardly extending hollow offset lug 14 which provides an upwardly opening recess 15 that is adapted to receive a guide plug 16 carried by the engine block. The cylindrical wall 13 is formed on its external surface with three annular grooves 17, 18 and 19, each of which is adapted to receive a piston ring (not illustrated) in accordance with well-known and conventional practices in this art. Below the lowermost groove 19 the bore which defines the clindrical wall 13 is enlarged lto provide a counterbore at 20 and this counterbore 20 is formed with screw threads to provide for the mounting of the head section H on the skirt section S as will be later described.

The skirt section S consists essentially of a cylindrical wall 21 which carries at the top a reduced extension 22. This reduced extension 22 is externally threaded with the threads complemental to the threads on the counterbore 20. Thus, the lower end of the skirt 13 is adapted to be screwed into the reduced extension 22.

It will be noted that the formation of the counterbore provides a shoulder at 23 on the cylindrical Wall 13. The reduced extension 22 has a top surface 24 opposite to the shoulder 23 and between the two there is positioned alock washer 25 which serves to prevent accidental disassembly of the respective sections.

Immediately beneath the reduced extension 22 the cylindrical wall 21 is formed with a pair of inwardly extending nipples 26 and 27 having aligned bores 28. These nipples 26 and 27 are formed integrally with the cylindrical wall 21.

A'wrist pin 29 is located in the aligned bores 28 and is held against longitudinal movement by a set screw.

31?. It will be noted that the inner end of the nipple 26 is enlarged to provide an annular ring 31 and the set screw 30 is screwed into a threaded passage 32 formed n this ring 31. The inner end of the set screw 30 is pointed as indicated at 33 and this pointed end is re Patented June 2, v1959 3 ceived in a complemental recess .formed in the wrist pin 29.

The wrist pin 29 is formed with a transverse oil passage 34 which extends in from one end thereof but not c0mpletely to the other end. The open end of the passage 34 is normally closed by plug 35.

The outer surface of the cylindrical wall 31 below the nipples 26 and 27 is formed with three oil retaining ducts 36, 37 and 38. A by-pass 39 connects the ducts 36 and 37 while another by-pass 40 connects the ducts 37 and 38.

A connecting rod is designated 41. The lower end of this connecting rod will be connected to a throw of the crank shaft of the engine in a well-known manner. The other, or upper, end is formed with a circular boss 42 that is positioned between the inner'end's of the nipples 2'6 and 27. This circular boss 42 is formed with a transverse lbore 43 that is lined with the bearing member 44. This bearing member 44 receives and encompasses the wrist pin 29. The bearing member 44 is formedv with three annular inwardly opening oil grooves 45, 46 and 47.

The connecting rod 41 is formed with an oil supply duct 48 which communicates withv the oilV supply of the engine which, of course, places the-oil` under pressure so that it will feed upwardly through the duct 48. The bearing member 44 and wrist pin 29 are formed with aligned radial passages 49 and 50 which establish communication between the supply duct 48 in the connecting rod and the transverse passage 34 in the wrist pin. It will be noted that the passage 49' opens into the annular groove 46 and the diameters of the passage 49 and supply duct 48 are suiciently large to accommodate the movement of the connecting rod 41 with respect to the wrist pin 29.

The inner end of the nipple 27 is also enlarged to form an annular ring 50. This annular ring 50 is formed with a radial aperture 51, the uper part of which is enlarged and threaded so as to accommodate a set screw 52. The lower end of the set screw 52 is pointed, as indicated at 53, and the pointed end is slotted. This pointed end is received in the smaller part of the passage 51 and this smaller part communicates with a radial passage 54 formed in the wrist pin 29 andwhich communicates with the transverse passage 34. The nipple 27 is also formed with a longitudinally extending passage S which cornmunicates on its inner end with the passage 51 and at its outer end opens onto the exterior of the cylinder. It will be noted that the set screw S2 is so constructed and mounted in the passage S1 as to positively preclude the possibility of blocking of the flow of oil from the transverse passage 34 to the outer wall of the cylinder.

After oil leaves the outer end of the passage 55 it will pass about the exterior of the piston due to the open spaces provided by the ends of the bores 28. It will be noted that a by-pass S6 establishes communication between one end of one of the lbores 28 and the upper oil duct 36.

A drip pan that is referred to in its entirety by the reference character D comprises a bottom wall 57 that is integrally joined to a cylindrical wall 58 which carries an outwardly extending tiange 59 that is secured to the block through the medium of the threaded stud 60. The bottom wall 57 carries an upwardly extending baie or separator 61 which is spaced inwardly from the cylindrical wall 21 of the section S. The bottom wall 57 is also formed with an elongated slot 62 which accommo dates the connecting rod 41. A conduit is shown at 63 asjconnected to the drip pan D and this conduit goes to a separator or filter.

Operation Whilethe mode of' operation and manner of lusing the sectional piston above described isbelieved to be obvious 4 from the illustration of the drawing and description of parts given, they may be briefly outlined as follows:

When it is desired to replace worn piston rings, the head section H may be removed from the skirt section S by simply unscrewing the threaded joint at 20. After the new rings have been installed the head section H is reassembled with the skirt section S in an obvious manner.

With the engine in which the piston S is included running oil under pressure is forced upwardly through the supply duct 48. From the latter it passes through the passages 49 and 50 into the transverse passage 34. From the latter it passes through the passages 54, 51 and 5S to the exterior of the piston. The oil will now move downwardly between the exterior surface of the piston and the cylinder wall 11 with the by-passes 56, 39 and 40 accommodating the movement. The oil retaining ducts 36, 37 and 38 will temporarily retain the oil at these locations. After the charge in the cylinder 11 has been iired the residue of water and gasolene together with oil will pass down into the drip pan D. From the latter it is conducted by the conduit 63 to a separator or filter so that the oil is conditioned for recirculation through the lubricating system.

The modification A slightly ymodified form of invention is illustrated in Figure 2. In this form of the invention the connecting rod 41 is solid and does not include the oil supply duct. In lieu thereof a tubular member 64 is employed. The upper end of the tubular member 64 passes through an appropriate passage 65 in the upper part of the connecting rod and then through the passages 49 and S0 in the bearing member 44 and circular boss 42 respectively. Otherwise, the construction is they same.

While preferred specification embodiments of the invention have hereinbefore been set forth, it is to -be clearly understood that the invention is not to be limited to the exact constructions, mechanisms and devices illustrated and described because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claim.

What is claimed is:

In a sectional piston, a head section comprising an end wall and a cylindrical wall integrally joined thereto with the cylindrical wall defining a bore that is enlarged at its lower end to form a counterbore, said counterbore being threaded and said cylindrical wall being formed with external grooves adapted to receive piston rings; and a skirt section comprising a cylindrical wall having an externally threaded reduced extension screwed into said counterbore, inwardly extending nipples carried by said skirt section and having. aligned bores, a wrist pin in said aligned bores having a longitudinal oil passage, radial passages connecting with saidlongitudinal passage, one of said radial passages connecting with a passage formed in one of said nipples and extending outwardly to the exterior of the piston and a connecting rod having an oil supply duct communicating with the other said radial passage in said wrist pin.

References Cited in the file of this patent UNITED STATES PATENTS 1,063,602 Russ June 3, 1913 1,951,959 Alexandrescu Mar. 20, 1934 1,978,714 Lentell Oct. 30, 1934 2,069,437 Frank Feb. 2, 1937 2,257,236 Hayden Sept. 30, 1941 2,436,043V Herreshoff et al. Feb; 17, 1948 2,674,506 Dow Apr.V 6, 1954 2,782,083 HeWSon Feb. 19, 1957 i mi d 

